Control of sustained casing pressure in wellbore annuli

Abstract

This invention provides a method for minimizing or relieving a sustained casing pressure in an annulus of a wellbore, where the annulus contains a first fluid having a density. The method comprises introducing a second fluid into the annulus. The second fluid has a density greater than the density of the first fluid and the second fluid is immiscible with the first fluid. The method is characterized in that the second fluid comprises at least one halogen-containing organic compound. The halogen-containing organic compound has one or more halogen atoms selected from fluorine, chlorine, bromine, and iodine, with the proviso that at least one of the halogen atoms is chlorine, bromine, or iodine.

1 . A method for minimizing or relieving a sustained casing pressure in an annulus of a wellbore, wherein the annulus contains a first fluid having a density, the method comprising introducing a second fluid into the annulus, wherein the second fluid has a density greater than the density of the first fluid and the second fluid is immiscible with the first fluid, characterized in that the second fluid comprises at least one halogen-containing organic compound, which halogen-containing organic compound has one or more halogen atoms selected from fluorine, chlorine, bromine, and iodine, with the proviso that at least one of the halogen atoms is chlorine, bromine, or iodine. 
     
     
         2 . A method as in  claim 1  wherein the halogen-containing compound is a bromine-containing organic compound, or wherein the halogen-containing compound is a chlorine-containing organic compound. 
     
     
         3 . A method as in  claim 2  wherein the bromine-containing organic compound is selected from the group consisting of brominated oils, brominated natural products, brominated fatty acids, brominated fatty esters, brominated oligomers and brominated polymers, bromine-containing aromatic compounds, bromine-containing nonaromatic organic compounds, bromine-containing ionic compounds, and mixtures of two or more of the foregoing. 
     
     
         4 . (canceled) 
     
     
         5 . A method as in  claim 2  wherein the chlorine-containing organic compound is selected from the group consisting of chlorinated oils, chlorinated natural products, chlorinated fatty acids, chlorinated fatty esters, chlorinated oligomers and chlorinated polymers, chlorine-containing aromatic compounds, chlorine-containing nonaromatic organic compounds, chlorine-containing ionic compounds, and mixtures of two or more of the foregoing. 
     
     
         6 . A method as in  claim 1  wherein the halogen-containing compound is a mixed-halogen organic compound. 
     
     
         7 . A method as in  claim 1  wherein the second fluid is a mixture of two or more halogen-containing organic compounds. 
     
     
         8 . A method as in  claim 7  wherein at least one of the halogen-containing organic compounds in the mixture is a bromine-containing organic compound. 
     
     
         9 . A method as in  claim 7  wherein at least one of the halogen-containing organic compounds in the mixture is a chlorine-containing organic compound. 
     
     
         10 . A method as in  claim 7  wherein at least one of the halogen-containing organic compounds in the mixture is an iodine-containing organic compound. 
     
     
         11 . A method as in  claim 3  wherein the bromine-containing organic compound is a bromine-containing nonaromatic organic compound. 
     
     
         12 . A method as in  claim 11  wherein the bromine-containing nonaromatic organic compound is a bromine-containing straight-chain compound. 
     
     
         13 . A method as in  claim 12  wherein the bromine-containing straight-chain compound is 1,1,2-tribromoethylene. 
     
     
         14 . A method as in  claim 3  wherein the bromine-containing organic compound is a bromine-containing aromatic organic compound. 
     
     
         15 . A method as in  claim 14  wherein the bromine-containing aromatic organic compound is a bromine-containing heterocyclic aromatic compound. 
     
     
         16 . A method as in  claim 15  wherein the bromine-containing heterocyclic aromatic compound is 2,5-dibromothiophene. 
     
     
         17 . A method as in  claim 14  wherein the bromine-containing aromatic organic compound is a bromine-containing homocyclic aromatic compound. 
     
     
         18 . A method as in  claim 17  wherein the bromine-containing homocyclic aromatic compound comprises a mixture of one or more dibromobenzenes and one or more tribromobenzenes. 
     
     
         19 . (canceled) 
     
     
         20 . A method as in  claim 1  wherein the introduction of the second fluid is continuous. 
     
     
         21 . A method as in  claim 1  wherein a portion of the first fluid is removed from the annulus. 
     
     
         22 . (canceled) 
     
     
         23 . A method as in  claim 1  wherein the halogen-containing organic compound has a halogen content of about 20 wt % or more. 
     
     
         24 . A method as in  claim 1  wherein the second fluid has a density that is higher than the density of the first fluid by about 0.5 ppg (0.06 kg/L) or more.